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Merge tag 'trace-printf-v6.13' of git://git.kernel.org/pub/scm/linux/kernel/git/trace...
[drm/drm-misc.git] / drivers / char / ipmi / ssif_bmc.c
bloba14fafc583d4d82ad27f69010ecd3339ab6bda14
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * The driver for BMC side of SSIF interface
4 *
5 * Copyright (c) 2022, Ampere Computing LLC
6 *
7 */
8
9 #include <linux/i2c.h>
10 #include <linux/miscdevice.h>
11 #include <linux/module.h>
12 #include <linux/of.h>
13 #include <linux/platform_device.h>
14 #include <linux/poll.h>
15 #include <linux/sched.h>
16 #include <linux/mutex.h>
17 #include <linux/spinlock.h>
18 #include <linux/timer.h>
19 #include <linux/jiffies.h>
20 #include <linux/ipmi_ssif_bmc.h>
21
22 #define DEVICE_NAME "ipmi-ssif-host"
23
24 #define GET_8BIT_ADDR(addr_7bit) (((addr_7bit) << 1) & 0xff)
25
26 /* A standard SMBus Transaction is limited to 32 data bytes */
27 #define MAX_PAYLOAD_PER_TRANSACTION 32
28 /* Transaction includes the address, the command, the length and the PEC byte */
29 #define MAX_TRANSACTION (MAX_PAYLOAD_PER_TRANSACTION + 4)
30
31 #define MAX_IPMI_DATA_PER_START_TRANSACTION 30
32 #define MAX_IPMI_DATA_PER_MIDDLE_TRANSACTION 31
33
34 #define SSIF_IPMI_SINGLEPART_WRITE 0x2
35 #define SSIF_IPMI_SINGLEPART_READ 0x3
36 #define SSIF_IPMI_MULTIPART_WRITE_START 0x6
37 #define SSIF_IPMI_MULTIPART_WRITE_MIDDLE 0x7
38 #define SSIF_IPMI_MULTIPART_WRITE_END 0x8
39 #define SSIF_IPMI_MULTIPART_READ_START 0x3
40 #define SSIF_IPMI_MULTIPART_READ_MIDDLE 0x9
41
42 /*
43 * IPMI 2.0 Spec, section 12.7 SSIF Timing,
44 * Request-to-Response Time is T6max(250ms) - T1max(20ms) - 3ms = 227ms
45 * Recover ssif_bmc from busy state if it takes up to 500ms
46 */
47 #define RESPONSE_TIMEOUT 500 /* ms */
48
49 struct ssif_part_buffer {
50 u8 address;
51 u8 smbus_cmd;
52 u8 length;
53 u8 payload[MAX_PAYLOAD_PER_TRANSACTION];
54 u8 pec;
55 u8 index;
56 };
57
58 /*
59 * SSIF internal states:
60 * SSIF_READY 0x00 : Ready state
61 * SSIF_START 0x01 : Start smbus transaction
62 * SSIF_SMBUS_CMD 0x02 : Received SMBus command
63 * SSIF_REQ_RECVING 0x03 : Receiving request
64 * SSIF_RES_SENDING 0x04 : Sending response
65 * SSIF_ABORTING 0x05 : Aborting state
66 */
67 enum ssif_state {
68 SSIF_READY,
69 SSIF_START,
70 SSIF_SMBUS_CMD,
71 SSIF_REQ_RECVING,
72 SSIF_RES_SENDING,
73 SSIF_ABORTING,
74 SSIF_STATE_MAX
75 };
76
77 struct ssif_bmc_ctx {
78 struct i2c_client *client;
79 struct miscdevice miscdev;
80 int msg_idx;
81 bool pec_support;
82 /* ssif bmc spinlock */
83 spinlock_t lock;
84 wait_queue_head_t wait_queue;
85 u8 running;
86 enum ssif_state state;
87 /* Timeout waiting for response */
88 struct timer_list response_timer;
89 bool response_timer_inited;
90 /* Flag to identify a Multi-part Read Transaction */
91 bool is_singlepart_read;
92 u8 nbytes_processed;
93 u8 remain_len;
94 u8 recv_len;
95 /* Block Number of a Multi-part Read Transaction */
96 u8 block_num;
97 bool request_available;
98 bool response_in_progress;
99 bool busy;
100 bool aborting;
101 /* Buffer for SSIF Transaction part*/
102 struct ssif_part_buffer part_buf;
103 struct ipmi_ssif_msg response;
104 struct ipmi_ssif_msg request;
105 };
106
107 static inline struct ssif_bmc_ctx *to_ssif_bmc(struct file *file)
108 {
109 return container_of(file->private_data, struct ssif_bmc_ctx, miscdev);
110 }
111
112 static const char *state_to_string(enum ssif_state state)
113 {
114 switch (state) {
115 case SSIF_READY:
116 return "SSIF_READY";
117 case SSIF_START:
118 return "SSIF_START";
119 case SSIF_SMBUS_CMD:
120 return "SSIF_SMBUS_CMD";
121 case SSIF_REQ_RECVING:
122 return "SSIF_REQ_RECVING";
123 case SSIF_RES_SENDING:
124 return "SSIF_RES_SENDING";
125 case SSIF_ABORTING:
126 return "SSIF_ABORTING";
127 default:
128 return "SSIF_STATE_UNKNOWN";
129 }
130 }
131
132 /* Handle SSIF message that will be sent to user */
133 static ssize_t ssif_bmc_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
134 {
135 struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file);
136 struct ipmi_ssif_msg msg;
137 unsigned long flags;
138 ssize_t ret;
139
140 spin_lock_irqsave(&ssif_bmc->lock, flags);
141 while (!ssif_bmc->request_available) {
142 spin_unlock_irqrestore(&ssif_bmc->lock, flags);
143 if (file->f_flags & O_NONBLOCK)
144 return -EAGAIN;
145 ret = wait_event_interruptible(ssif_bmc->wait_queue,
146 ssif_bmc->request_available);
147 if (ret)
148 return ret;
149 spin_lock_irqsave(&ssif_bmc->lock, flags);
150 }
151
152 if (count < min_t(ssize_t,
153 sizeof_field(struct ipmi_ssif_msg, len) + ssif_bmc->request.len,
154 sizeof(struct ipmi_ssif_msg))) {
155 spin_unlock_irqrestore(&ssif_bmc->lock, flags);
156 ret = -EINVAL;
157 } else {
158 count = min_t(ssize_t,
159 sizeof_field(struct ipmi_ssif_msg, len) + ssif_bmc->request.len,
160 sizeof(struct ipmi_ssif_msg));
161 memcpy(&msg, &ssif_bmc->request, count);
162 ssif_bmc->request_available = false;
163 spin_unlock_irqrestore(&ssif_bmc->lock, flags);
164
165 ret = copy_to_user(buf, &msg, count);
166 }
167
168 return (ret < 0) ? ret : count;
169 }
170
171 /* Handle SSIF message that is written by user */
172 static ssize_t ssif_bmc_write(struct file *file, const char __user *buf, size_t count,
173 loff_t *ppos)
174 {
175 struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file);
176 struct ipmi_ssif_msg msg;
177 unsigned long flags;
178 ssize_t ret;
179
180 if (count < sizeof(msg.len) ||
181 count > sizeof(struct ipmi_ssif_msg))
182 return -EINVAL;
183
184 if (copy_from_user(&msg, buf, count))
185 return -EFAULT;
186
187 if (!msg.len || msg.len > IPMI_SSIF_PAYLOAD_MAX ||
188 count < sizeof_field(struct ipmi_ssif_msg, len) + msg.len)
189 return -EINVAL;
190
191 spin_lock_irqsave(&ssif_bmc->lock, flags);
192 while (ssif_bmc->response_in_progress) {
193 spin_unlock_irqrestore(&ssif_bmc->lock, flags);
194 if (file->f_flags & O_NONBLOCK)
195 return -EAGAIN;
196 ret = wait_event_interruptible(ssif_bmc->wait_queue,
197 !ssif_bmc->response_in_progress);
198 if (ret)
199 return ret;
200 spin_lock_irqsave(&ssif_bmc->lock, flags);
201 }
202
203 /*
204 * The write must complete before the response timeout fired, otherwise
205 * the response is aborted and wait for next request
206 * Return -EINVAL if the response is aborted
207 */
208 ret = (ssif_bmc->response_timer_inited) ? 0 : -EINVAL;
209 if (ret)
210 goto exit;
211
212 del_timer(&ssif_bmc->response_timer);
213 ssif_bmc->response_timer_inited = false;
214
215 memcpy(&ssif_bmc->response, &msg, count);
216 ssif_bmc->is_singlepart_read = (msg.len <= MAX_PAYLOAD_PER_TRANSACTION);
217
218 ssif_bmc->response_in_progress = true;
219
220 /* ssif_bmc not busy */
221 ssif_bmc->busy = false;
222
223 /* Clean old request buffer */
224 memset(&ssif_bmc->request, 0, sizeof(struct ipmi_ssif_msg));
225 exit:
226 spin_unlock_irqrestore(&ssif_bmc->lock, flags);
227
228 return (ret < 0) ? ret : count;
229 }
230
231 static int ssif_bmc_open(struct inode *inode, struct file *file)
232 {
233 struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file);
234 int ret = 0;
235
236 spin_lock_irq(&ssif_bmc->lock);
237 if (!ssif_bmc->running)
238 ssif_bmc->running = 1;
239 else
240 ret = -EBUSY;
241 spin_unlock_irq(&ssif_bmc->lock);
242
243 return ret;
244 }
245
246 static __poll_t ssif_bmc_poll(struct file *file, poll_table *wait)
247 {
248 struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file);
249 __poll_t mask = 0;
250
251 poll_wait(file, &ssif_bmc->wait_queue, wait);
252
253 spin_lock_irq(&ssif_bmc->lock);
254 /* The request is available, userspace application can get the request */
255 if (ssif_bmc->request_available)
256 mask |= EPOLLIN;
257
258 spin_unlock_irq(&ssif_bmc->lock);
259
260 return mask;
261 }
262
263 static int ssif_bmc_release(struct inode *inode, struct file *file)
264 {
265 struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file);
266
267 spin_lock_irq(&ssif_bmc->lock);
268 ssif_bmc->running = 0;
269 spin_unlock_irq(&ssif_bmc->lock);
270
271 return 0;
272 }
273
274 /*
275 * System calls to device interface for user apps
276 */
277 static const struct file_operations ssif_bmc_fops = {
278 .owner = THIS_MODULE,
279 .open = ssif_bmc_open,
280 .read = ssif_bmc_read,
281 .write = ssif_bmc_write,
282 .release = ssif_bmc_release,
283 .poll = ssif_bmc_poll,
284 };
285
286 /* Called with ssif_bmc->lock held. */
287 static void complete_response(struct ssif_bmc_ctx *ssif_bmc)
288 {
289 /* Invalidate response in buffer to denote it having been sent. */
290 ssif_bmc->response.len = 0;
291 ssif_bmc->response_in_progress = false;
292 ssif_bmc->nbytes_processed = 0;
293 ssif_bmc->remain_len = 0;
294 ssif_bmc->busy = false;
295 memset(&ssif_bmc->part_buf, 0, sizeof(struct ssif_part_buffer));
296 wake_up_all(&ssif_bmc->wait_queue);
297 }
298
299 static void response_timeout(struct timer_list *t)
300 {
301 struct ssif_bmc_ctx *ssif_bmc = from_timer(ssif_bmc, t, response_timer);
302 unsigned long flags;
303
304 spin_lock_irqsave(&ssif_bmc->lock, flags);
305
306 /* Do nothing if the response is in progress */
307 if (!ssif_bmc->response_in_progress) {
308 /* Recover ssif_bmc from busy */
309 ssif_bmc->busy = false;
310 ssif_bmc->response_timer_inited = false;
311 /* Set aborting flag */
312 ssif_bmc->aborting = true;
313 }
314
315 spin_unlock_irqrestore(&ssif_bmc->lock, flags);
316 }
317
318 /* Called with ssif_bmc->lock held. */
319 static void handle_request(struct ssif_bmc_ctx *ssif_bmc)
320 {
321 /* set ssif_bmc to busy waiting for response */
322 ssif_bmc->busy = true;
323 /* Request message is available to process */
324 ssif_bmc->request_available = true;
325 /* Clean old response buffer */
326 memset(&ssif_bmc->response, 0, sizeof(struct ipmi_ssif_msg));
327 /* This is the new READ request.*/
328 wake_up_all(&ssif_bmc->wait_queue);
329
330 /* Armed timer to recover slave from busy state in case of no response */
331 if (!ssif_bmc->response_timer_inited) {
332 timer_setup(&ssif_bmc->response_timer, response_timeout, 0);
333 ssif_bmc->response_timer_inited = true;
334 }
335 mod_timer(&ssif_bmc->response_timer, jiffies + msecs_to_jiffies(RESPONSE_TIMEOUT));
336 }
337
338 static void calculate_response_part_pec(struct ssif_part_buffer *part)
339 {
340 u8 addr = part->address;
341
342 /* PEC - Start Read Address */
343 part->pec = i2c_smbus_pec(0, &addr, 1);
344 /* PEC - SSIF Command */
345 part->pec = i2c_smbus_pec(part->pec, &part->smbus_cmd, 1);
346 /* PEC - Restart Write Address */
347 addr = addr | 0x01;
348 part->pec = i2c_smbus_pec(part->pec, &addr, 1);
349 part->pec = i2c_smbus_pec(part->pec, &part->length, 1);
350 if (part->length)
351 part->pec = i2c_smbus_pec(part->pec, part->payload, part->length);
352 }
353
354 static void set_singlepart_response_buffer(struct ssif_bmc_ctx *ssif_bmc)
355 {
356 struct ssif_part_buffer *part = &ssif_bmc->part_buf;
357
358 part->address = GET_8BIT_ADDR(ssif_bmc->client->addr);
359 part->length = (u8)ssif_bmc->response.len;
360
361 /* Clear the rest to 0 */
362 memset(part->payload + part->length, 0, MAX_PAYLOAD_PER_TRANSACTION - part->length);
363 memcpy(&part->payload[0], &ssif_bmc->response.payload[0], part->length);
364 }
365
366 static void set_multipart_response_buffer(struct ssif_bmc_ctx *ssif_bmc)
367 {
368 struct ssif_part_buffer *part = &ssif_bmc->part_buf;
369 u8 part_len = 0;
370
371 part->address = GET_8BIT_ADDR(ssif_bmc->client->addr);
372 switch (part->smbus_cmd) {
373 case SSIF_IPMI_MULTIPART_READ_START:
374 /*
375 * Read Start length is 32 bytes.
376 * Read Start transfer first 30 bytes of IPMI response
377 * and 2 special code 0x00, 0x01.
378 */
379 ssif_bmc->nbytes_processed = 0;
380 ssif_bmc->block_num = 0;
381 part->length = MAX_PAYLOAD_PER_TRANSACTION;
382 part_len = MAX_IPMI_DATA_PER_START_TRANSACTION;
383 ssif_bmc->remain_len = ssif_bmc->response.len - part_len;
384
385 part->payload[0] = 0x00; /* Start Flag */
386 part->payload[1] = 0x01; /* Start Flag */
387
388 memcpy(&part->payload[2], &ssif_bmc->response.payload[0], part_len);
389 break;
390
391 case SSIF_IPMI_MULTIPART_READ_MIDDLE:
392 /*
393 * IPMI READ Middle or READ End messages can carry up to 31 bytes
394 * IPMI data plus block number byte.
395 */
396 if (ssif_bmc->remain_len <= MAX_IPMI_DATA_PER_MIDDLE_TRANSACTION) {
397 /*
398 * This is READ End message
399 * Return length is the remaining response data length
400 * plus block number
401 * Block number 0xFF is to indicate this is last message
402 *
403 */
404 /* Clean the buffer */
405 memset(&part->payload[0], 0, MAX_PAYLOAD_PER_TRANSACTION);
406 part->length = ssif_bmc->remain_len + 1;
407 part_len = ssif_bmc->remain_len;
408 ssif_bmc->block_num = 0xFF;
409 part->payload[0] = ssif_bmc->block_num;
410 } else {
411 /*
412 * This is READ Middle message
413 * Response length is the maximum SMBUS transfer length
414 * Block number byte is incremented
415 * Return length is maximum SMBUS transfer length
416 */
417 part->length = MAX_PAYLOAD_PER_TRANSACTION;
418 part_len = MAX_IPMI_DATA_PER_MIDDLE_TRANSACTION;
419 part->payload[0] = ssif_bmc->block_num;
420 ssif_bmc->block_num++;
421 }
422
423 ssif_bmc->remain_len -= part_len;
424 memcpy(&part->payload[1], ssif_bmc->response.payload + ssif_bmc->nbytes_processed,
425 part_len);
426 break;
427
428 default:
429 /* Do not expect to go to this case */
430 dev_err(&ssif_bmc->client->dev, "%s: Unexpected SMBus command 0x%x\n",
431 __func__, part->smbus_cmd);
432 break;
433 }
434
435 ssif_bmc->nbytes_processed += part_len;
436 }
437
438 static bool supported_read_cmd(u8 cmd)
439 {
440 if (cmd == SSIF_IPMI_SINGLEPART_READ ||
441 cmd == SSIF_IPMI_MULTIPART_READ_START ||
442 cmd == SSIF_IPMI_MULTIPART_READ_MIDDLE)
443 return true;
444
445 return false;
446 }
447
448 static bool supported_write_cmd(u8 cmd)
449 {
450 if (cmd == SSIF_IPMI_SINGLEPART_WRITE ||
451 cmd == SSIF_IPMI_MULTIPART_WRITE_START ||
452 cmd == SSIF_IPMI_MULTIPART_WRITE_MIDDLE ||
453 cmd == SSIF_IPMI_MULTIPART_WRITE_END)
454 return true;
455
456 return false;
457 }
458
459 /* Process the IPMI response that will be read by master */
460 static void handle_read_processed(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
461 {
462 struct ssif_part_buffer *part = &ssif_bmc->part_buf;
463
464 /* msg_idx start from 0 */
465 if (part->index < part->length)
466 *val = part->payload[part->index];
467 else if (part->index == part->length && ssif_bmc->pec_support)
468 *val = part->pec;
469 else
470 *val = 0;
471
472 part->index++;
473 }
474
475 static void handle_write_received(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
476 {
477 /*
478 * The msg_idx must be 1 when first enter SSIF_REQ_RECVING state
479 * And it would never exceeded 36 bytes included the 32 bytes max payload +
480 * the address + the command + the len and the PEC.
481 */
482 if (ssif_bmc->msg_idx < 1 || ssif_bmc->msg_idx > MAX_TRANSACTION)
483 return;
484
485 if (ssif_bmc->msg_idx == 1) {
486 ssif_bmc->part_buf.length = *val;
487 ssif_bmc->part_buf.index = 0;
488 } else {
489 ssif_bmc->part_buf.payload[ssif_bmc->part_buf.index++] = *val;
490 }
491
492 ssif_bmc->msg_idx++;
493 }
494
495 static bool validate_request_part(struct ssif_bmc_ctx *ssif_bmc)
496 {
497 struct ssif_part_buffer *part = &ssif_bmc->part_buf;
498 bool ret = true;
499 u8 cpec;
500 u8 addr;
501
502 if (part->index == part->length) {
503 /* PEC is not included */
504 ssif_bmc->pec_support = false;
505 ret = true;
506 goto exit;
507 }
508
509 if (part->index != part->length + 1) {
510 ret = false;
511 goto exit;
512 }
513
514 /* PEC is included */
515 ssif_bmc->pec_support = true;
516 part->pec = part->payload[part->length];
517 addr = GET_8BIT_ADDR(ssif_bmc->client->addr);
518 cpec = i2c_smbus_pec(0, &addr, 1);
519 cpec = i2c_smbus_pec(cpec, &part->smbus_cmd, 1);
520 cpec = i2c_smbus_pec(cpec, &part->length, 1);
521 /*
522 * As SMBus specification does not allow the length
523 * (byte count) in the Write-Block protocol to be zero.
524 * Therefore, it is illegal to have the last Middle
525 * transaction in the sequence carry 32-byte and have
526 * a length of ‘0’ in the End transaction.
527 * But some users may try to use this way and we should
528 * prevent ssif_bmc driver broken in this case.
529 */
530 if (part->length)
531 cpec = i2c_smbus_pec(cpec, part->payload, part->length);
532
533 if (cpec != part->pec)
534 ret = false;
535
536 exit:
537 return ret;
538 }
539
540 static void process_request_part(struct ssif_bmc_ctx *ssif_bmc)
541 {
542 struct ssif_part_buffer *part = &ssif_bmc->part_buf;
543 unsigned int len;
544
545 switch (part->smbus_cmd) {
546 case SSIF_IPMI_SINGLEPART_WRITE:
547 /* save the whole part to request*/
548 ssif_bmc->request.len = part->length;
549 memcpy(ssif_bmc->request.payload, part->payload, part->length);
550
551 break;
552 case SSIF_IPMI_MULTIPART_WRITE_START:
553 ssif_bmc->request.len = 0;
554
555 fallthrough;
556 case SSIF_IPMI_MULTIPART_WRITE_MIDDLE:
557 case SSIF_IPMI_MULTIPART_WRITE_END:
558 len = ssif_bmc->request.len + part->length;
559 /* Do the bound check here, not allow the request len exceed 254 bytes */
560 if (len > IPMI_SSIF_PAYLOAD_MAX) {
561 dev_warn(&ssif_bmc->client->dev,
562 "Warn: Request exceeded 254 bytes, aborting");
563 /* Request too long, aborting */
564 ssif_bmc->aborting = true;
565 } else {
566 memcpy(ssif_bmc->request.payload + ssif_bmc->request.len,
567 part->payload, part->length);
568 ssif_bmc->request.len += part->length;
569 }
570 break;
571 default:
572 /* Do not expect to go to this case */
573 dev_err(&ssif_bmc->client->dev, "%s: Unexpected SMBus command 0x%x\n",
574 __func__, part->smbus_cmd);
575 break;
576 }
577 }
578
579 static void process_smbus_cmd(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
580 {
581 /* SMBUS command can vary (single or multi-part) */
582 ssif_bmc->part_buf.smbus_cmd = *val;
583 ssif_bmc->msg_idx = 1;
584 memset(&ssif_bmc->part_buf.payload[0], 0, MAX_PAYLOAD_PER_TRANSACTION);
585
586 if (*val == SSIF_IPMI_SINGLEPART_WRITE || *val == SSIF_IPMI_MULTIPART_WRITE_START) {
587 /*
588 * The response maybe not come in-time, causing host SSIF driver
589 * to timeout and resend a new request. In such case check for
590 * pending response and clear it
591 */
592 if (ssif_bmc->response_in_progress)
593 complete_response(ssif_bmc);
594
595 /* This is new request, flip aborting flag if set */
596 if (ssif_bmc->aborting)
597 ssif_bmc->aborting = false;
598 }
599 }
600
601 static void on_read_requested_event(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
602 {
603 if (ssif_bmc->state == SSIF_READY ||
604 ssif_bmc->state == SSIF_START ||
605 ssif_bmc->state == SSIF_REQ_RECVING ||
606 ssif_bmc->state == SSIF_RES_SENDING) {
607 dev_warn(&ssif_bmc->client->dev,
608 "Warn: %s unexpected READ REQUESTED in state=%s\n",
609 __func__, state_to_string(ssif_bmc->state));
610 ssif_bmc->state = SSIF_ABORTING;
611 *val = 0;
612 return;
613
614 } else if (ssif_bmc->state == SSIF_SMBUS_CMD) {
615 if (!supported_read_cmd(ssif_bmc->part_buf.smbus_cmd)) {
616 dev_warn(&ssif_bmc->client->dev, "Warn: Unknown SMBus read command=0x%x",
617 ssif_bmc->part_buf.smbus_cmd);
618 ssif_bmc->aborting = true;
619 }
620
621 if (ssif_bmc->aborting)
622 ssif_bmc->state = SSIF_ABORTING;
623 else
624 ssif_bmc->state = SSIF_RES_SENDING;
625 }
626
627 ssif_bmc->msg_idx = 0;
628
629 /* Send 0 if there is nothing to send */
630 if (!ssif_bmc->response_in_progress || ssif_bmc->state == SSIF_ABORTING) {
631 *val = 0;
632 return;
633 }
634
635 if (ssif_bmc->is_singlepart_read)
636 set_singlepart_response_buffer(ssif_bmc);
637 else
638 set_multipart_response_buffer(ssif_bmc);
639
640 calculate_response_part_pec(&ssif_bmc->part_buf);
641 ssif_bmc->part_buf.index = 0;
642 *val = ssif_bmc->part_buf.length;
643 }
644
645 static void on_read_processed_event(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
646 {
647 if (ssif_bmc->state == SSIF_READY ||
648 ssif_bmc->state == SSIF_START ||
649 ssif_bmc->state == SSIF_REQ_RECVING ||
650 ssif_bmc->state == SSIF_SMBUS_CMD) {
651 dev_warn(&ssif_bmc->client->dev,
652 "Warn: %s unexpected READ PROCESSED in state=%s\n",
653 __func__, state_to_string(ssif_bmc->state));
654 ssif_bmc->state = SSIF_ABORTING;
655 *val = 0;
656 return;
657 }
658
659 /* Send 0 if there is nothing to send */
660 if (!ssif_bmc->response_in_progress || ssif_bmc->state == SSIF_ABORTING) {
661 *val = 0;
662 return;
663 }
664
665 handle_read_processed(ssif_bmc, val);
666 }
667
668 static void on_write_requested_event(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
669 {
670 if (ssif_bmc->state == SSIF_READY || ssif_bmc->state == SSIF_SMBUS_CMD) {
671 ssif_bmc->state = SSIF_START;
672
673 } else if (ssif_bmc->state == SSIF_START ||
674 ssif_bmc->state == SSIF_REQ_RECVING ||
675 ssif_bmc->state == SSIF_RES_SENDING) {
676 dev_warn(&ssif_bmc->client->dev,
677 "Warn: %s unexpected WRITE REQUEST in state=%s\n",
678 __func__, state_to_string(ssif_bmc->state));
679 ssif_bmc->state = SSIF_ABORTING;
680 return;
681 }
682
683 ssif_bmc->msg_idx = 0;
684 ssif_bmc->part_buf.address = *val;
685 }
686
687 static void on_write_received_event(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
688 {
689 if (ssif_bmc->state == SSIF_READY ||
690 ssif_bmc->state == SSIF_RES_SENDING) {
691 dev_warn(&ssif_bmc->client->dev,
692 "Warn: %s unexpected WRITE RECEIVED in state=%s\n",
693 __func__, state_to_string(ssif_bmc->state));
694 ssif_bmc->state = SSIF_ABORTING;
695
696 } else if (ssif_bmc->state == SSIF_START) {
697 ssif_bmc->state = SSIF_SMBUS_CMD;
698
699 } else if (ssif_bmc->state == SSIF_SMBUS_CMD) {
700 if (!supported_write_cmd(ssif_bmc->part_buf.smbus_cmd)) {
701 dev_warn(&ssif_bmc->client->dev, "Warn: Unknown SMBus write command=0x%x",
702 ssif_bmc->part_buf.smbus_cmd);
703 ssif_bmc->aborting = true;
704 }
705
706 if (ssif_bmc->aborting)
707 ssif_bmc->state = SSIF_ABORTING;
708 else
709 ssif_bmc->state = SSIF_REQ_RECVING;
710 }
711
712 /* This is response sending state */
713 if (ssif_bmc->state == SSIF_REQ_RECVING)
714 handle_write_received(ssif_bmc, val);
715 else if (ssif_bmc->state == SSIF_SMBUS_CMD)
716 process_smbus_cmd(ssif_bmc, val);
717 }
718
719 static void on_stop_event(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
720 {
721 if (ssif_bmc->state == SSIF_READY ||
722 ssif_bmc->state == SSIF_START ||
723 ssif_bmc->state == SSIF_SMBUS_CMD ||
724 ssif_bmc->state == SSIF_ABORTING) {
725 dev_warn(&ssif_bmc->client->dev,
726 "Warn: %s unexpected SLAVE STOP in state=%s\n",
727 __func__, state_to_string(ssif_bmc->state));
728 ssif_bmc->state = SSIF_READY;
729
730 } else if (ssif_bmc->state == SSIF_REQ_RECVING) {
731 if (validate_request_part(ssif_bmc)) {
732 process_request_part(ssif_bmc);
733 if (ssif_bmc->part_buf.smbus_cmd == SSIF_IPMI_SINGLEPART_WRITE ||
734 ssif_bmc->part_buf.smbus_cmd == SSIF_IPMI_MULTIPART_WRITE_END)
735 handle_request(ssif_bmc);
736 ssif_bmc->state = SSIF_READY;
737 } else {
738 /*
739 * A BMC that receives an invalid request drop the data for the write
740 * transaction and any further transactions (read or write) until
741 * the next valid read or write Start transaction is received
742 */
743 dev_err(&ssif_bmc->client->dev, "Error: invalid pec\n");
744 ssif_bmc->aborting = true;
745 }
746 } else if (ssif_bmc->state == SSIF_RES_SENDING) {
747 if (ssif_bmc->is_singlepart_read || ssif_bmc->block_num == 0xFF)
748 /* Invalidate response buffer to denote it is sent */
749 complete_response(ssif_bmc);
750 ssif_bmc->state = SSIF_READY;
751 }
752
753 /* Reset message index */
754 ssif_bmc->msg_idx = 0;
755 }
756
757 /*
758 * Callback function to handle I2C slave events
759 */
760 static int ssif_bmc_cb(struct i2c_client *client, enum i2c_slave_event event, u8 *val)
761 {
762 unsigned long flags;
763 struct ssif_bmc_ctx *ssif_bmc = i2c_get_clientdata(client);
764 int ret = 0;
765
766 spin_lock_irqsave(&ssif_bmc->lock, flags);
767
768 switch (event) {
769 case I2C_SLAVE_READ_REQUESTED:
770 on_read_requested_event(ssif_bmc, val);
771 break;
772
773 case I2C_SLAVE_WRITE_REQUESTED:
774 on_write_requested_event(ssif_bmc, val);
775 break;
776
777 case I2C_SLAVE_READ_PROCESSED:
778 on_read_processed_event(ssif_bmc, val);
779 break;
780
781 case I2C_SLAVE_WRITE_RECEIVED:
782 on_write_received_event(ssif_bmc, val);
783 break;
784
785 case I2C_SLAVE_STOP:
786 on_stop_event(ssif_bmc, val);
787 break;
788
789 default:
790 dev_warn(&ssif_bmc->client->dev, "Warn: Unknown i2c slave event\n");
791 break;
792 }
793
794 if (!ssif_bmc->aborting && ssif_bmc->busy)
795 ret = -EBUSY;
796
797 spin_unlock_irqrestore(&ssif_bmc->lock, flags);
798
799 return ret;
800 }
801
802 static int ssif_bmc_probe(struct i2c_client *client)
803 {
804 struct ssif_bmc_ctx *ssif_bmc;
805 int ret;
806
807 ssif_bmc = devm_kzalloc(&client->dev, sizeof(*ssif_bmc), GFP_KERNEL);
808 if (!ssif_bmc)
809 return -ENOMEM;
810
811 spin_lock_init(&ssif_bmc->lock);
812
813 init_waitqueue_head(&ssif_bmc->wait_queue);
814 ssif_bmc->request_available = false;
815 ssif_bmc->response_in_progress = false;
816 ssif_bmc->busy = false;
817 ssif_bmc->response_timer_inited = false;
818
819 /* Register misc device interface */
820 ssif_bmc->miscdev.minor = MISC_DYNAMIC_MINOR;
821 ssif_bmc->miscdev.name = DEVICE_NAME;
822 ssif_bmc->miscdev.fops = &ssif_bmc_fops;
823 ssif_bmc->miscdev.parent = &client->dev;
824 ret = misc_register(&ssif_bmc->miscdev);
825 if (ret)
826 return ret;
827
828 ssif_bmc->client = client;
829 ssif_bmc->client->flags |= I2C_CLIENT_SLAVE;
830
831 /* Register I2C slave */
832 i2c_set_clientdata(client, ssif_bmc);
833 ret = i2c_slave_register(client, ssif_bmc_cb);
834 if (ret)
835 misc_deregister(&ssif_bmc->miscdev);
836
837 return ret;
838 }
839
840 static void ssif_bmc_remove(struct i2c_client *client)
841 {
842 struct ssif_bmc_ctx *ssif_bmc = i2c_get_clientdata(client);
843
844 i2c_slave_unregister(client);
845 misc_deregister(&ssif_bmc->miscdev);
846 }
847
848 static const struct of_device_id ssif_bmc_match[] = {
849 { .compatible = "ssif-bmc" },
850 { },
851 };
852 MODULE_DEVICE_TABLE(of, ssif_bmc_match);
853
854 static const struct i2c_device_id ssif_bmc_id[] = {
855 { DEVICE_NAME },
856 { }
857 };
858 MODULE_DEVICE_TABLE(i2c, ssif_bmc_id);
859
860 static struct i2c_driver ssif_bmc_driver = {
861 .driver = {
862 .name = DEVICE_NAME,
863 .of_match_table = ssif_bmc_match,
864 },
865 .probe = ssif_bmc_probe,
866 .remove = ssif_bmc_remove,
867 .id_table = ssif_bmc_id,
868 };
869
870 module_i2c_driver(ssif_bmc_driver);
871
872 MODULE_AUTHOR("Quan Nguyen <quan@os.amperecomputing.com>");
873 MODULE_AUTHOR("Chuong Tran <chuong@os.amperecomputing.com>");
874 MODULE_DESCRIPTION("Linux device driver of the BMC IPMI SSIF interface.");
875 MODULE_LICENSE("GPL");
Kernel DRM miscellaneous fixes and cross-tree changes